Generating treatment fluid for use in dialysis therapy

Abstract

A system is configured to generate treatment fluid for use in dialysis by mixing water with one or more liquid concentrates (Cx). The system comprises a fluid path arrangement (L), an input port arrangement in fluid communication with the fluid path arrangement, and a heater (9). The input port arrangement is configured for releasable connection to a set of containers (7) holding the one or more liquid concentrates. The system is operated to perform time-separated sessions of generating treatment fluid. The system is further operated, between the sessions and by use of the heater (9), to perform a first heat disinfection of the fluid path arrangement except for a subset thereof. The system is further operated to arrange at least one of the one or more liquid concentrates in the subset between the time-separated sessions.

Description

[0001] GENERATING TREATMENT FLUID FOR USE IN DIALYSIS THERAPY

[0002] Technical Field

[0003] The present disclosure relates generally to dialysis therapy, and in particular to systems for generating treatment fluid for use in dialysis and techniques for operating such systems.

[0004] Background Art

[0005] Dialysis therapy is a therapy that replaces the normal blood-filtering function of the kidneys. It is used when the kidneys are not working well, which is known as kidney failure and includes acute kidney injury (AKI) and chronic kidney disease (CKD). Dialysis involves removal of water from the blood of the patient suffering from kidney failure, as well as exchange of solutes with the blood. One example of dialysis therapy is peritoneal dialysis (PD), in which a treatment fluid is infused into the peritoneal cavity of the patient to interface with the blood of the patient through the peritoneal membrane. Another example of dialysis therapy is extracorporeal (EC) blood therapy, in which blood is circulated outside of the patient and interfaced with one or more treatment fluids. Modalities of extracorporeal blood therapy include hemodialysis (HD), hemofiltration (HF) and hemodiafiltration (HDF).

[0006] Treatment fluids used in PD and HD are commonly known as dialysis fluids. In HF, the treatment fluid is known as replacement fluid, since it is infused into the blood of the patient to replace fluid removed during therapy. In HDF, both dialysis fluid and replacement fluid are used.

[0007] Dialysis therapy is typically automated and performed under control of a dialysis machine. In PD, the machine is known as a cycler, which is connected in fluid communication with the peritoneal cavity and is operated to control the flow of fresh dialysis fluid into the peritoneal cavity and the flow of spent dialysis fluid from the peritoneal cavity. In EC blood therapy, there are two main categories of machines: "chronic machines" for treatment of patient suffering from CKD, and "acute machines" for treatment of patients suffering from AKI.

[0008] Over time, dialysis therapy consumes large quantities of medical fluid. In some modalities of dialysis therapy, pre-made medical fluid is delivered in prefilled bags to the point of care. For example, conventional automated PD is performed by use of prefilled bags. AKI machines are configured to use prefilled bags of medical fluid, by staff installing a prefilled bag before treatment, and replacing the prefilled bag as required. On the other hand, CKD machines have integrated capability to generate treatment fluid by mixing one or more concentrates with water. Recently, PD machines with integrated capability of fluid generation have been proposed.

[0009] There is a general desire to advance generation of treatment fluid for all types of dialysis therapy. It is also desirable for the generation of treatment fluid to be made in a system made up of re-usable or permanent components to the largest extent possible. This will both minimize the environmental impact, by reducing the amount of components that go to waste, as well as reduce the need for manual intervention by the user to prepare the system for fluid generation. The provision of re-usable or permanent components in a system for generation of treatment fluid results in a need to implement a technique of controlling the microbial activity in the system. It is desirable for such a technique to limit the need for manual intervention by the user.

[0010] Summary

[0011] It is an objective to at least partly overcome one or more limitations of the prior art.

[0012] One objective is to provide a user-friendly system for generation of treatment fluid for use in dialysis therapy.

[0013] Another objective is to provide such a system that includes a function for controlling microbial activity in the system when the system is not used for fluid generation.

[0014] One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by systems for generating treatment fluid, a computer-implemented method, and a computer-readable medium according to the independent claims, embodiments thereof being defined by the dependent claims.

[0015] The present disclosure proposes a technique for fluid generation that may be implemented in a dialysis machine or in a stand-alone machine for fluid generation. The technique may be used for generating treatment fluid on-demand for use in on-going dialysis therapy, or for generating treatment fluid for intermediate storage in advance of dialysis therapy. In the proposed technique, a mixing arrangement is provided for generating treatment fluid by mixing water with liquid concentrate(s), and a fluid path arrangement is provided for directing the water and the liquid concentrate^ ) to and through the mixing arrangement and for directing the treatment fluid from the mixing arrangement for use in dialysis. A port arrangement is provided to allow container(s) with the liquid concentrate(s) to be releasably connected for fluid communication with the fluid path arrangement. Microbial activity in the system is controlled through a combination of heat disinfection and filling / priming part of the system with at least one liquid concentrate. The use of priming is based on an insight that sole use of heat disinfection would require the container(s) to be disconnected from the port arrangement before heat disinfection, to enable the fluid path arrangement to be disinfected all the way to the port arrangement. The liquid concentrate is assumed to have the ability of controlling microbial activity, which is true for most liquid concentrates contemplated for use in generating of treatment fluid for dialysis. The combination of heat disinfection and priming allows the container(s) to remain connected to the system between sessions of fluid generation. This facilitates the handling of the system for the user and removes need for port disinfection to handle touch contamination as the concentrates are not removed. The proposed technique also reduces the waste of container material, assuming that the alternative would be to disconnect and discard the container(s) after each session of fluid generation. By allowing the container(s) to remain connected between sessions, the proposed technique may also reduce the waste of concentrate since the concentrate in the container may be used over plural sessions. Compared to the alternative of manually disconnecting the container(s) after each session and manually reconnecting the container(s) before each session, the proposed technique also reduces the risk for contact contamination of the port arrangement.

[0016] Still other objectives, aspects, embodiments and technical effects, as well as features and advantages may appear from the following detailed description, from the attached claims as well as from the drawings.

[0017] Brief Description of the Drawings

[0018] FIG. 1A is a block diagram of an example dialysis system configured for generation of PD fluid, FIGS 1B-1C show the dialysis system of FIG. 1A in example operating states, FIG. 1C is an example timeline chart for the operating states in FIGS 1B-1C, and FIG. IE is an example timeline chart for a PD therapy session and associated PD fluid generation.

[0019] FIG. 2 is a flow chart of an example method of operating a system for generation of treatment fluid.

[0020] FIG. 3 is a block diagram of an example apparatus including a system for generation of treatment fluid.

[0021] FIGS 4A-4B are block diagrams of a system for generation of treatment fluid in accordance with a detailed example, and FIGS 4C-4D are schematic views of valve types used in the system of FIGS 4A-4B.

[0022] FIGS 5A-5B depict the system of FIGS 4A-4B during generation of treatment fluid. FIG. 6 depicts the system in FIGS 4A-4B during a first-type heat disinfection.

[0023] FIG. 7 depicts the system in FIGS 4A-4B during a second-type heat disinfection.

[0024] FIGS 8A-8B depict a part of the system in FIGS 4A-4B during a concentrate priming operation.

[0025] FIGS 9A-9C depict an alternative configuration of the system in FIGS 4A-4B during a concentrate priming operation and a first-type heat disinfection.

[0026] FIGS 10A-10B are section views of an example port in a connected state and a disconnected state, respectively.

[0027] FIG. 11 is a block diagram of an example control arrangement.

[0028] Detailed Description of Example Embodiments

[0029] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements.

[0030] Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and / or operational aspects of any of the embodiments described and / or contemplated herein may be included in any of the other embodiments described and / or contemplated herein, and / or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and / or vice versa, unless explicitly stated otherwise. As used herein, "at least one" shall mean "one or more" and these phrases are intended to be interchangeable. Accordingly, the terms "a" and / or "an" shall mean "at least one" or "one or more", even though the phrase "one or more" or "at least one" is also used herein. As used herein, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.

[0031] As used herein, the terms "multiple", "plural" and "plurality" are intended to imply provision of two or more elements, whereas the term "set" is intended to imply provision of one or more elements. The term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0032] It will furthermore be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing the scope of the present disclosure.

[0033] Like reference signs refer to like elements throughout.

[0034] Well-known functions or constructions may not be described in detail for brevity and / or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0035] As used herein, "dialysis therapy" or "dialysis" refers to any therapy that replaces or supplements the renal function of a patient by use of a treatment fluid. Dialysis therapy includes, without limitation, extracorporeal (EC) blood therapy and peritoneal dialysis (PD) therapy.

[0036] As used herein, "treatment fluid" refers to any fluid that is consumed as a result of dialysis therapy. Treatment fluid includes, without limitation, dialysis fluid for infusion into the peritoneal cavity during PD therapy, dialysis fluid for supply to a dialyzer during EC blood therapy, and replacement fluid and substitution fluid for infusion into blood during EC blood therapy.

[0037] As used herein, "heat disinfection" refers to a technique of deactivating bacteria and viruses by subjecting them to a fluid at a required temperature for a required time period. The fluid may be water, optionally in combination with a cleaning agent ("disinfectant").

[0038] As used herein, "AO concept" refers to an established technique of quantifying the effect of heat disinfection on deactivation of microorganisms. An AO value may be calculated according to: AO = IQU-80) / 2. t?where T is the fluid temperature (in °C), z is a bacteria coefficient, and At is the exposure time at the fluid temperature. By use of this equation, a value of the microbial deactivation may be calculated, by summation or integration, during heat-up, holding, and cooling of any moist heat disinfection process. For example, a condition for sufficient heat disinfection may be that the AO value is at least 500, 600, 700, 800 or 900. Generally, the fluid temperature needs to exceed 65 °C to be effective.

[0039] The present disclosure relates to a technique of ensuring the microbial integrity over time in a system for generating treatment fluid, both while the system is operated in a session for fluid production and between sessions. The technique is applicable to systems for generation of treatment fluid for either peritoneal dialysis (PD) therapy or extracorporeal (EC) blood therapy. While the technique is mainly described and exemplified herein with reference to PD therapy, the skilled person has no difficulty of applying the technique to other forms of dialysis therapy. FIG. 1A is a generic overview of a dialysis system 1 for PD therapy. The dialysis system 1 is fluidly connected to the peritoneal cavity PC of a patient P. As indicated by a double-ended arrow, the dialysis system 1 is operable to convey fresh dialysis fluid into PC and to receive spent dialysis fluid from PC on a fluid path 2. The fluid path 2 may be defined by tubing that connects to an implanted catheter (not shown) in fluid communication with the peritoneal cavity PC. A drain line 3 is connected to the dialysis system 1 for conveying the spent dialysis fluid to a drain 4, for example a floor drain, a toilet, a sink, a bag, or a container. PD therapy is typically implemented as daily treatment sessions, each comprising a number of fluid exchange cycles. The respective fluid exchange cycle may include a fill phase, a dwell phase and a drain phase, performed in sequence. In the fill phase, fresh dialysis fluid is supplied to PC on fluid path 2. In the dwell phase, the dialysis fluid resides in PC. In the drain phase, spent dialysis fluid is extracted from PC on fluid path 2.

[0040] In the illustrated example, the dialysis system 1 includes a therapy system 20, which is operable to control the flows of fresh and spent treatment fluid, and a fluid preparation system 10 ("FPS"), which is operable to generate the treatment fluid for the therapy system 20 by mixing product water with one or more liquid concentrates. The FPS 10 and the therapy system 20 may be implemented as a single machine or as separate machines. The product water is received from a source 5 on a water supply line 6. The product water is purified water that may be produced to meet criteria of so-called "water for dialysis" "water for injection", or "ultrapure water". The source 5 may be a centralized water purification appliance that produces product water for a plurality of dialysis systems, or a local water purification device that is operated to process tap water into product water for use by the dialysis system 1. In some embodiments, as exemplified in FIG.1A, the water source 5 and the FPS 10 are separate machines that are fluidly connected. In other embodiments, the water source 5 is integrated with the FPS 10.

[0041] As indicated schematically in FIG. 1A, the FPS 10 includes a mixing arrangement (or sub-system) 11 and a fluid path arrangement (or sub-system) L. The mixing arrangement 11 is operable to mix the product water with liquid concentrate(s) to generate treatment fluid ("PD fluid"). The mixing arrangement 11 may comprise a mixing chamber, an in-line mixer, an injector mixer, or any other conventional device for mixing liquids. The mixing arrangement 11 may be configured to generate the PD fluid in batches or on the fly. Here, "on the fly" (or "online") implies that the PD fluid is generated by continuously mixing the liquid concentrate(s) into the product water as the product water flows through the mixing arrangement 11. The fluid path arrangement L includes all durable fluid paths within the FPS 10, as well as fluid pumps and valves that are associated with the durable fluid paths and exposed to the fluid that flows along the durable fluid paths. As used herein, "durable" implies that the fluid paths are installed in the FPS 10 to be reused. In other words, the fluid path arrangement L consists of reusable components. Such reusable components need to be intermittently disinfected to counteract microbial growth to the extent that the reusable components are in contact with fluid during operation of the FPS 10. The reusable components may be configured to be kept in the system at least throughout the duration of a plurality of consecutive fluid generation sessions (FGSs, below). In other words, the reusable components are not replaced over an extended time period during which the FPS 10 is operated to perform a plurality of consecutive fluid generation sessions. In practice, the reusable components are typically permanently installed in the FPS 10 and not intended or configured to be replaced by the user of the FPS 10 but rather by a service technician whenever a reusable component is malfunctioning or has reached its nominal end of life.

[0042] The liquid concentrate is a consumable that is supplied from a container or bag ("concentrate container"), which is connected for fluid communication with the FPS 10. In the example of FIG. 1 A, a liquid concentrate Cx is held in a concentrate container 7, which is removably connected to the FPS 10 of the dialysis system 1. The container 7 is thus a disposable unit that is regularly disconnected and replaced for a new container full of concentrate Cx. For example, the container 7 may be replaced when the remaining amount of concentrate Cx is deemed insufficient, or when a predefined time has elapsed since the container 7 was installed for use by the FPS 10. The container 7 may be attached directly to the FPS 10 or via a disposable tubing 8, as shown.

[0043] FIG. IB illustrates the dialysis system 1 in three operating states of the FPS 10, designated I- III, in accordance with an example. The operating states I- III are performed in sequence, as indicated by block arrows. Operating state I results in a session for generation of PD fluid ("fluid generation session" or FGS), and operating states II and III are intermediate states which are performed between consecutive FGSs to mitigate bacterial growth within the FPS 10. In one example, the FGS is performed once a day or once every second days.

[0044] It should be noted that the container 7 is fluidly connected to the FPS 10 throughout and between operating states I-III in FIG. IB. This is beneficial for several reasons. Compared to the alternative of discarding the container 7 after each FGS (state I), the number of containers to be discarded can be reduced significantly when one container is used for plural FGSs. Thus, the amount of waste material is significantly reduced. Further, the accumulated amount of residual concentrate to be discarded is likely to be reduced when one container is used for plural FGSs. It is conceivable to have the user disconnect the partly depleted container 7 after each FGS and then reconnect the container before the next FGS. However, this will result in additional work for the user. Here, the user may be a caretaker or the patient itself. A practice that involves frequent manual disconnection and re-connection of the container 7 will also dramatically increase the risk for touch contamination and thereby potentially expose the patient to microbial contamination.

[0045] In operating state I of FIG. IB, the FPS 10 obtains product water from the water source 5, and concentrate Cx from the container 7, as indicated by solid arrows in the supply line 6 and the disposable tubing 8. The FPS 10 is operated to produce PD fluid, by directing the water and the concentrates through the mixing arrangement 11 by use of the fluid path arrangement L. As indicated by a dashed arrow in the fluid path 2, the PD fluid may be supplied to the peritoneal cavity via the fluid path 2 during the generation. Alternatively, the PD fluid may be stored within the FPS 10 or the therapy system 20 pending a future therapy session. It is also conceivable that state I is performed while the dialysis system 1 has not yet been connected to or is disconnected from the patient. The FPS 10 may also intermittently direct fluid to the drain 4 during state I, as indicated by a dot-dashed arrows in the drain line 3. For example, the PD fluid with an incorrect composition may be directed to the drain 4, for example before start of the FGS.

[0046] In operating state II of FIG. IB, the FPS 10 is operated to perform a heat disinfection of a selected portion of the fluid path arrangement L ("first-type heat disinfection" or "first heat disinfection"). It is also likely that the mixing arrangement 11 is heat disinfected in state II. The first heat disinfection involves operating one or more heaters 9 in the FPS 10 to heat a disinfection fluid and distribute the heated disinfection fluid within the selected portion of the fluid path arrangement L. In the illustrated example, the disinfection fluid is product water from the source 5, as indicated by a solid arrow in the supply line 6, and at least part of the heated fluid is sent to drain during state II, as indicated by a solid arrow in the drain line 3. In a variant, FPS 10 is configured to produce the disinfection fluid by mixing water with a disinfectant, which may be accessible to the FPS 10 from a source (not shown) in fluid communication with the fluid path arrangement L.

[0047] The selected portion is typically a major portion of the fluid path arrangement L, but a subset of the fluid path arrangement L is excluded from heat disinfection. It would be desirable to perform the heat disinfection of the entire fluid path arrangement L, but this is difficult to achieve without disconnecting the container 7 (and the tubing 8 in the example of FIG. IB). When the container 7 remains fluidly connected to the FPS 10 during the heat disinfection, the fluid path arrangement L needs to be operated to prevent heated fluid from entering the container 7 (and / or the tubing 8). This will inevitably result in a subset of the fluid path arrangement L being inaccessible for the heat disinfection in state II. In the following, this non-disinfected subset is denoted "remaining subset" and may alternatively be denoted "excluded subset".

[0048] Although not shown in FIG. IB, the FPS 10 comprises one or more ports for connection to the container 7, optionally via the disposable tubing 8. As used herein, all ports on the FPS 10 for inlet of concentrate are collectively denoted "input port arrangement" or "input port sub-system", which is in fluid communication with the fluid path arrangement L. The above-mentioned remaining or excluded subset, which is not heat disinfected in state II, is configured for fluid communication with the input port arrangement. Typically, the remaining subset is directly joined to the input port arrangement, so that the respective concentrate Cx enters the fluid path arrangement L via the remaining subset.

[0049] In operating state III of FIG. IB, the FPS 10 is operated to fill the remaining subset, and possibly further parts of the fluid path arrangement L, with the concentrate Cx from the container 7, as indicated by a solid arrow in the disposable tubing 8. Also, fluid is directed from the FPS 10 to the drain 4, as indicated by a solid arrow in the drain line 3. Thus, state III results in the remaining subset being filled or "primed" with the concentrate Cx and is also denoted "intermittent priming state" herein. Many concentrates that have been proposed for use in generation of PD fluid are unfavorable for microbial growth, and some concentrates are even bacteriostatic fluids. It may also be noted that the concentrate in a concentrate container is sterile. A bacteriostatic fluid comprises a bacteriostatic agent, which is a biological or chemical agent that stops bacterial growth, or even kills bacteria (also known as bactericidal agent). For example, many electrolyte concentrates and glucose concentrates proposed for generation of PD fluid are inherently bacteriostatic. Thus, also a combined electrolyte and glucose concentrate may be bacteriostatic. Similarly, many concentrates for use in generation of treatment fluid for use in EC blood dialysis are unfavorable for microbial growth or bacteriostatic. If an extrinsic component is included in a concentrate to make it bacteriostatic, such a component has to be chosen with care so as to not have any unwanted or questionable effects on the produced treatment fluid. It is currently believed that any concentrate with a water activity (aw) of about 0.87 or lower is suitable for priming the remaining subset in state III.

[0050] If the FPS 10 is connected to plural containers with concentrates, the remaining subset may be subdivided into partitions associated with the respective container. Each such partition may be filled with concentrate from its associated container. Alternatively, two or more partitions may be filled with concentrate from one and the same container. For example, it may be desirable to fill a different concentrate into a partition associated with a container that holds a concentrate deemed unsuitable for use in state III.

[0051] In an alternative approach, a container that holds a concentrate deemed unsuitable for use in state III may be disconnected from its port in the port arrangement after each fluid generation session, and the first heat disinfection (state II) may be performed to disinfect this port and fluid paths leading to this port. These fluid paths are thus not included in the remaining subset.

[0052] The present disclosure presumes that the FPS 10 is connected to a set of containers during each fluid generation session, and that at least one container in the set of container holds a liquid concentrate that is suitable for use in state III. Each such container may remain connected to its respective port in the input port arrangement during the first heat disinfection (state II). The remaining subset is configured for fluid communication with the port(s) that remain connected to container(s) during the first heat disinfection.

[0053] It is to be noted that FIG. IB is an example. The remaining subset may be primed with concentrate(s) in other ways. In one variant, state III is performed before the disinfection in state II, for example directly upon completion of state I. In such a variant, the disinfection in state II is performed for all relevant fluid paths of the FPS 10 other than the remaining subset, which has been primed with concentrate(s) in the preceding state III. In another variant, at least part of the remaining subset is primed with concentrate(s) already when the FPS 10 is in state I, i.e., during generation of treatment fluid, or in a preparation phase before the FPS 10 enters state I. If all of the remaining subset is primed in state I and / or in the preparatory phase, a separate state III need not be performed since its functionality is embedded into state I and / or the preparatory phase. If only part of the remaining subset is primed with concentrate(s) after state I, the FPS 10 may attain state III after state I to prime the non-primed part of the remaining subset with concentrate(s).

[0054] The FPS 10 may be operable in additional operating states, shown in FIG. 1C and designated IV and V, to further mitigate bacterial growth within the FPS 10. The operating states IV and V may be performed in sequence whenever the container 7 is disconnected from the FPS 10, for example when a new container is to be installed. In some embodiments, the container 7 will be replaced every 7-14 days. Other embodiments are described further below.

[0055] In operating state IV of FIG. 1C, the FPS 10 is operated to perform a further heat disinfection of at least the remaining subset from operating state II ("second-type heat disinfection" or "second heat disinfection"). It is conceivable that state IV results in a heat disinfection of the entire fluid path arrangement L, as well as the mixing arrangement 11. Like the heat disinfection in state II, the second heat disinfection in state IV involves operating one or more heaters 9 in the FPS 10 to heat a fluid and distribute the heated fluid within the fluid path arrangement L. In the illustrated example, the fluid is product water from the source 5, as indicated by a solid arrow in the supply line 6, and at least part of the heated fluid is sent to drain during state IV, as indicated by a solid arrow in the drain line 3. Heat disinfection of the remaining subset is rendered simple when the container 7 is disconnected from a connecting port on the FPS 10, and the connecting port is closed / sealed. As noted above, the disinfection fluid that is used in the heat disinfection may contain a disinfectant, which may be supplied to the FPS 10 from a source (not shown) of disinfectant. In some embodiments, the FPS 10 instructs the user to connect the source of disinfectant to the connecting port when the container 7 has been disconnected, and then operates to obtain the disinfectant from the source and mix the disinfectant with water to generate the disinfection fluid. Before the second heat disinfection is started, the FPS 10 instructs the user to disconnect the source from the connecting port.

[0056] The FPS 10 attains the operating state V of FIG. 1C when a new container 7 has been fluidly connected to the FPS 10. In some embodiments, the FPS 10 includes a sensor for detecting that a container 7 has been installed on the connecting port. It is also conceivable that the FPS 10 is operated to test the concentrate in the respective container, by extracting the concentrate from the container and passing it through a conductivity sensor in the FPS 10 (cf. S5 in FIG. 4A). If the measured conductivity is within a predefined range, the FPS 10 proceeds to use the concentrate, otherwise the user is instructed to take proper action, for example change the container.

[0057] In state V, the FPS 10 is operated to fill the remaining subset, and possibly further parts of the fluid path arrangement L, with the concentrate Cx from the container 7, as indicated by a solid arrow in the disposable tubing 8. Also, fluid is directed from the FPS 10 to drain 4, as indicated by a solid arrow in the drain line 3. Thus, state V results in the remaining subset being primed with the concentrate Cx and is also denoted "preparatory priming state" herein. After state V, the FPS 10 is ready to enter a preparatory phase leading to state I. State V may but need not be identical to state III.

[0058] In a specific embodiment, state V replaces state III. Thus, when a container 7 has been connected to the FPS 10, the FPS 10 attains the preparatory priming state V to prime the remaining subset, and possibly further parts of the fluid path arrangement L, with concentrate from this container 7. The remaining subset then remains filled with the concentrate until the container 7 is disconnected and the FPS 10 attains state IV to perform the second heat disinfection, in which the remaining subset is flushed and disinfected. Even if it is conceivable, as noted above, that part of the remaining subset is inherently flushed with the concentrate during state I, this part of remaining subset still contains the concentrate during such flushing. Omitting state III will reduce the amount of concentrate that is used for priming instead of generating treatment fluid. This embodiment will be further discussed in the following with reference to FIG. ID. Also, detailed examples of the preparatory priming state V are given below with reference to FIGS 8-9.

[0059] It is to be understood that the foregoing discussion about suitable or desirable properties of the concentrate(s) for use in the intermittent priming state III is equally applicable to the preparatory priming state V.

[0060] FIG. ID is a timing diagram of an example sequence of operating states attained by the FPS 10 in FIG. 1A. In the illustrated example, it is assumed that the amount of concentrate in one container is sufficient for use in five fluid generation sessions. In each fluid generation session, the FPS 10 is in state I. The sessions are separated by a respective time interval Atl. After the five fluid generation sessions, the existing container is replaced for a new container full of concentrate, at time CC. In the illustrated example, the container is replaced after an in-use period At2. The existing container need not be changed directly after the fifth fluid generation session, but may be changed at any time point before start of the forthcoming fluid generation session. When the existing container has been disconnected, at time CC, the FPS is set in state IV to perform the second heat disinfection. Then, when a new container has been connected, the FPS is set in state V to fill the remaining subset with the concentrate from the new container. When a fluid generation session (state I) is completed, the FPS 10 is set in state II to perform the first heat disinfection. The remaining subset, which has been filled with concentrate by state V, is unaffected by the first heat disinfection. As described above, state III may be performed in connection with state II to prime the remaining subset, or part thereof, with concentrate. However, as indicated by parentheses in FIG. ID, state III is optional. In the specific embodiment described above, the concentrate is instead left in at least part of the remaining subset throughout the rest of the in-use period At2 after state V. The purpose of arranging concentrate in the remaining subset is to mitigate microbial growth and allow the container to remain attached to the FPS throughout the in-use period At2. It is conceivable that the FPS attains state III at least once during the in-use period At2 to replace or supplement the concentrate in the remaining subset, or part thereof. For example, state III may be attained when the concentrate has resided in the remaining subset for more than a maximum duration, at which microbial growth may occur in the remaining subset. The maximum duration may be given by the concentrate(s) that are used for priming the remaining subset in state V. It is conceivable that the maximum duration is set to account for other factors, such as the risk for water leaking into the remaining subset to dilute the concentrate(s) therein. The maximum duration may, for example, be at least 1-7 days.

[0061] The in-use period At2 may similarly be at least 1-7 days. In some embodiments, the in-use period At2 is in the range of 3-7 days, for example 3, 4, 5, 6 or 7 days. In some embodiments, the FPS 10 is configured to perform the sequence of time-separated sessions (states I) over a time period of at least 1-7 days, such as over a time period of 3, 4, 5, 6 or 7 days, while the container 7 remains connected to the input port arrangement of the FPS 10 throughout this time period. As described above, the FPS 10 may be set in state III during the in-use period At2 to replace or supplement the concentrate in the remaining subset by admitting new concentrate from the container 7 into the remaining subset. This use of state III will extend the in-use period At2 beyond the maximum duration.

[0062] The timing diagram is an example of a general method of operating an FPS, including: a) performing a sequence of time- separated sessions of generating treatment fluid ("fluid generation sessions", FGSs), b) performing, between the sessions, a first heat disinfection of the fluid path arrangement except for the remaining subset, and c) arranging at least one concentrate in the remaining subset between the sessions. Thereby, the remaining subset contains the concentrate(s) throughout the respective time interval Atl. The method provides the technical advantage of allowing concentrate container(s) to remain attached to the FPS between the sessions. In the example of FIG. ID, concentrate(s) are arranged in the remaining subset by the preparatory priming state V, optionally supplemented by one or more intermittent priming states III during the in use-period At2. The concentrate(s) may also be arranged in the remaining subset during the respective session (during state I). In some embodiments, the remaining subset contains the concentrate(s) from state V until the end of the in-use period At2. In a variant, the remaining subset only contains the concentrate(s) between a subset of the sessions in the in-use period At2. In the example of FIG. ID, the concentrate(s) may be arranged in the remaining subset between one or two pairs of sessions during the in-use period At2. This may be achieved through state V or state III. It is also conceivable that the preparatory priming state V does not result in a (complete) priming of the remaining subset with the concentrate(s), but that this priming is achieved through one or more intermittent priming states III.

[0063] FIG. IE is given as an example of the relation between a fluid generation session (FGS) and a session of PD dialysis (PDS). In FIG. IE, the FPS 10 is in state I throughout the FGS, but is only actively operated to generate PD fluid during time periods designated by FG. The PDS comprises fill phases (FP), dwell phases (DWP) and drain phases (DP), as is well known to the skilled person. In the illustrated example, the PDS includes five dwell phases and starts with a fill phase and ends with a drain phase. During the dwell phase, the therapy system 20 is inactive, whereas it is operative during the fill and drain phases. In the illustrated example, the FPS 10 is operated in synchronization with the PDS, so as to perform the fluid generation (FG) during the respective dwell phase (DWP). Thereby, PD fluid for a subsequent fill phase is generated during the preceding dwell phase. Further, a fluid generation (FG) is performed in advance of the first fill phase.

[0064] Thus, as shown in FIG. IE, the FPS 10 may be operated to perform the respective fluid generation session (FGS) to generate treatment fluid for use in a corresponding therapy session of peritoneal dialysis (PD). Further, as shown in FIG. IE, such a therapy session may comprise a plurality of fill phases, in which the treatment fluid is supplied to a peritoneal cavity of a dialysis patient. For example, therapy sessions for PD may be performed once a day, or once every second days. In some embodiments, the time interval (cf. Atl in FIG. ID) between consecutive FGS s is at least 4, 6, 8, 10 or 12 hours. In some embodiments, there is a one-to-one correspondence between FGS and PDS, such that the treatment fluid that is generated by a respective FGS is consumed during the corresponding PDS. Any treatment fluid that may remain at completion of the PDS may be discarded, for example by being pumped to drain (4 in FIG. 1A).

[0065] FIG. IE is merely given for context and is not intended to be limiting in any respect. Depending on the configuration of the FPS 10 and the therapy system 20, the fluid generation need not be performed during dwell phases, nor need the FGS be subdivided into FGs. Even if the consumption of treatment fluid is quite different in EC blood therapy, the skilled person realizes that the FPS 10 and its operating states as described hereinabove are equally applicable to generation of treatment fluid for such therapy. For example, the FPS 10 may be operated to perform the respective fluid generation session (FGS) to generate treatment fluid for use in a respective therapy session of EC blood therapy, and the time interval between consecutive FGSs may be at least 4, 6, 8, 10 or 12 hours.

[0066] FIG. 2 is a flowchart of an example method 100 that may be performed by a control arrangement for operating an FPS 10. In FIG. 2, the FPS 10 may be connected to any number of concentrate containers containing any number of different concentrates that are to be mixed with product water to form a treatment fluid. An example of a control arrangement 80 is given in FIG. 11 and described further below. In FIG. 2, dashed boxes indicate optional steps. In step 101, the FPS 10 is operated to generate treatment fluid, from one or more concentrates and product water and by use of the mixing arrangement 11. By step 101, the FPS 10 is set in state I (FIG. IB). Step 101 is performed in time-separated sessions (FGSs), which are separated by a respective time interval (cf. Atl in FIG. ID).

[0067] In step 102, which is performed between consecutive FGSs, the FPS 10 is operated to perform a first heat disinfection of the fluid path arrangement L except for the above-mentioned remaining subset, which is configured for fluid communication with the above-mentioned input port arrangement of the FPS 10. By step 102, the FPS 10 is set in state II (FIG. IB). Any valves and / or fluid pumps in the fluid path arrangement L, as well as the mixing arrangement 11 may also be heat disinfected in step 102. As indicated in FIG. 2, step 102 may involve operating one or more valves in the fluid path arrangement L to define the remaining subset within the fluid path arrangement L. Generally, the fluid path arrangement L may be seen to be made up of a first subset and a second subset, where the first subset is the remaining subset and the second subset contains all other components of the fluid path arrangement L. Step 102 may involve operating the fluid path arrangement L to fluidly separate the first subset from the second subset before the first heat disinfection, so as to prevent fluid transfer between the first and second subsets. In step 103, the FPS 10 is operated to arrange one or more concentrates to reside in the remaining subset between the FGSs. This means that the remaining subset ("first subset") contains the concentrate(s) at least between the FGSs. Typically, the remaining subset also contains the concentrate(s) during the respective FGS. As noted, step 103 may involve at least one priming operation to supply the concentrate(s) to the remaining subset via the input port arrangement. In some embodiments, for example as shown in FIG. ID, such a priming operation may be performed by setting the FPS in the preparatory priming state V (FIG. 1C) when a container has been connected to the input port arrangement. It is also conceivable that the concentrate(s) in the remaining subset is intermittently replaced, for example as part of the FGS or by switching the FPS to the intermittent priming state III (FIG. IB). It should be noted that all concentrates that are available to FPS 10 need not be used in step 103. As mentioned above, one or more concentrates among the available concentrates may be excluded if deemed unsuitable for use in step 103.

[0068] As discussed, the combination of steps 102 and 103 allows the concentrate container(s) to remain attached to the FPS 10 between the time- separated FGSs. Thus, in some embodiments, even if step 102 does not require access to any concentrate, step 102 is performed while the input port arrangement remains connected to the concentrate container(s). In some embodiments, the respective concentrate used in step 103 is bacteriostatic. This will enable a relatively long in-use period (cf. At2 in FIG. ID) and / or time interval between FGSs (cf. Atl in FIG. ID).

[0069] The method 100 may include a step 104 of evaluating if the residence time of the concentrate(s) in the remaining subset exceeds a predefined maximum time, and take dedicated action when the residence time exceeds the predefined maximum time. The residence time is the time since the respective concentrate was introduced into the remaining subset. The maximum time may be a nominal value set for the specific concentrate(s) used in step 103, to represent an elevated risk for microbial growth. Step 104 is thus a safety procedure to ensure that it does not go unnoticed if the maximum time is exceeded. In some embodiments, the dedicated action comprises alerting the user that maximum time has been exceeded, via a feedback device (cf. 84 in FIG. 11). In some embodiments, the dedicated action comprises stopping the operation of the FPS 10. In some embodiments, the dedicated action comprises causing the concentrate container(s) to be disconnected from the input port arrangement and performing the second heat disinfection of step 105 (below) when all concentrate containers are disconnected. For example, the user may be instructed via the feedback device to disconnect the concentrate container(s). By performing the second heat disinfection, any potential microbial activity in the remaining subset is eliminated. In some embodiments, the dedicated action comprises setting the FPS 10 in state III, by which a priming operation is initiated to replace the concentrate(s) in the remaining subset.

[0070] As shown, the method 100 may include a step 105, which is performed when all concentrate containers have been disconnected from the input port arrangement of the FPS 10. In step 105, the FPS 10 is operated to perform a second heat disinfection of at least the remaining subset and the input port arrangement. Thus, by step 105, the FPS 10 is set in state IV (FIG. 1C). As indicated in FIG. 2, the second heat disinfection in step 105 need not be restricted to the remaining subset, but may be performed to heat disinfect all fluid paths of the fluid path arrangement L. Any valves and / or fluid pumps in the fluid path arrangement L, as well as the mixing arrangement 11 may also be heat disinfected in step 105.

[0071] In some embodiments, the FPS 10 includes one or more port sensors for detecting disconnection and / or connection of the respective concentrate container, and step 105 is performed only when the port sensor(s) indicate that all concentrate containers have been disconnected from the input port arrangement, and the input port arrangement is closed. In some embodiments, it may be sufficient to detect that the input port arrangement is closed, if a closed input port arrangement inherently implies that all relevant concentrate containers have been disconnected from the input port arrangement. For example, a connecting port in the input arrangement may be configured so that it cannot be closed unless it is disconnected from any concentrate container. An example of such a connecting port is shown in FIGS 10A-10B and described further below.

[0072] The port sensor may include any type of device for sensing presence or absence of a connector associated with a concentrate container, for example an electromechanical switch, a Hall sensor, a reed switch, an optical sensor, etc. Further, the port sensor may include a similar device to sense that the respective inlet opening of the input port arrangement is closed after disconnection of a concentrate container, for example by sensing presence or absence of a cover (cf. lid 71 in FIGS 10A-10B). The use of port sensors improves the operational reliability of the FPS 10. If the second heat disinfection is performed while a concentrate container is connected to the FPS 10, the heated fluid may enter the concentrate container to dilute or even destroy the concentrate therein.

[0073] The method 100 is also shown to include a step 106, which is performed when all concentrate containers have been re-connected to the input port arrangement of the FPS 10. Step 106 is performed after step 105. In step 106, the FPS 10 is operated to fill at least the remaining subset with the concentrate(s) via the input port arrangement. Thus, by step 106, the FPS 10 is set in state V (FIG. 1C). Step 106 may be part of step 103.

[0074] FIG. 3 is a block diagram of an example apparatus 10' that includes an FPS 10 and a source 5 of product water. In the illustrated example, the FPS 10 and the source 5 are encased within a housing that exposes a plurality of ports Pla, Plb, P2, P3, P4a, P4b. The source 5 may be a water purification device, which is configured to receive and process source water SW, for example tap water, into product water PW. The source 5 is in fluid communication with a water port Pla for source water. A tubing 5a extends from a SW source (not shown) and has terminal connector 5a', which is connected to the port Pla. In the following, it is assumed that the source 5 is disinfected separately from the FPS 10. The disinfection of the source 5 will not be further described.

[0075] The FPS 10 comprises a plurality of internal fluid lines connected to the source 5 and to the ports Plb, P2, P3, P4a, P4b. These internal fluid lines are part of the above- mentioned fluid path arrangement L. For simplicity, the FPS 10 is illustrated to comprise a main sub-system 40, which includes the above-mentioned mixing arrangement 11, as well as further fluid lines, valves, and fluid pumps that are part of the fluid path arrangement L. In FIG. 3, the apparatus 10' is shown during production of treatment fluid TF, by thicker lines indicating passage of fluid.

[0076] A fluid line L5 extends from the source 5 to the main sub-system 40 to provide the product water PW. A fluid line ("inlet line") L2 extends from a concentrate port P2 to the main sub-system 40. The port P2 is an input port for concentrate Cx. A terminal connector 8 a on a tubing 8 that extends to a concentrate container (not shown) is releasably connected to the port P2 to direct the concentrate to the FPS 10. Thus, in this example, the above-mentioned input port arrangement includes only port P2. A port sensor 12 is arranged at the port P2 to detect when the connector 8a is attached to the port P2. A fluid line L3 extends from the main sub-system 40 to a first drain port P3, which is arranged to output discarded fluid for transport to drain (not shown, cf. 4 in FIGS 1A-1C). A tubing 3 is connected by a terminal connector 3 a to the port P3 and extends to drain.

[0077] The port P lb is a supply port for treatment fluid TF and is arranged to receive TF from the main sub-system 40 on fluid line LI. A terminal connector 21a on a disposable tubing 21 is releasably connected to the supply port Plb to direct TF to a therapy system (not shown). The port P4a is a return port for spent treatment fluid from the therapy system. A terminal connector 22a on a disposable tubing 22 is releasably connected to the port P4a to provide the spent treatment fluid from the therapy system to the apparatus 10'. A fluid line L4 extends from the port P4a to a second drain port P4b, which is arranged to output the spent treatment fluid for transport to drain. A tubing 3' is connected by a terminal connector 3a' to the port P4b and extends to drain.

[0078] In the illustrated example, the internal lines of the FPS 10 include a plurality of auxiliary fluid lines AL1, AL2 and AL5, which are used during heat disinfection to enable disinfection of relevant fluid lines and ports. In other words, the auxiliary fluid lines are arranged to avoid dead ends that cannot be disinfected in the fluid path arrangement L. Thus, AL5 is arranged to enable the main sub-system 40 to circulate heated fluid through L5 and AL5, AL1 is arranged to enable the main sub- system 40 to circulate heated fluid through LI, Plb and AL1, and AL2 is arranged to enable the main sub-system 40 to circulate heated fluid through L2, P2 and AL2.

[0079] The above-mentioned remaining subset that is not disinfected in step 102 includes at least L2 and AL2 in the example of FIG. 3. It is realized that if heated fluid is circulated through L2, P2 and AL2 when the terminal connector 8 a is attached to the port P2, it is not unlikely that the heated fluid will enter the tubing 8 and possibly the concentrate container at the other end of the tubing 8.

[0080] The method 100 in FIG. 2 will be further described with reference to a detailed example of an FPS 10 shown in FIGS 4A-4B. The FPS 10 is fluidly connected to a source 5 of product water by two fluid lines L5, L5', which are connected to a circulation line 50 in the source 5 at a respective connection point Cl, C2. Although not shown in FIGS 4A-4B, the source 5 is operable to circulate product water through the circulation line 50. The source 5 and the FPS 10 may or may not be integrated into a common apparatus. With reference to FIG. 3, L5' may correspond to AL5.

[0081] The FPS 10 comprises a main fluid line ("main line") LI which extends from a 3- way valve V4 (FIG. 4A) to a supply port Plb (FIG. 4B) for output of treatment fluid. The FPS 10 is arranged within a casing 60, which is configured to expose two ports P2, P2' for connection to a respective concentrate container 7, 7'. The containers 7, 7' contain a respective concentrate that forms part of the treatment fluid. In the following, these concentrates are referred to as first and second concentrates. In the example of PD fluid, one of the concentrates may contain an osmotic agent, such as glucose, and the other concentrate may contain a plurality of different electrolytes. In the example of treatment fluid for use in EC blood therapy, one of the concentrates may be a B concentrate and the other concentrate may be an A concentrate, as is well known in the art. In the illustrated example, the ports P2, P2' are releasably connected to terminal connectors 8a, 8a' on tubings 8, 8' in fluid communication with the containers 7, 7'. Fluid lines ("input lines") L2, L2' extend from the ports P2, P2' to the main line LI. Fluid pumps FP2, FP3 in the input lines L2, L2' are operable to pump the respective concentrate into the main line LI. The ports P2, P2' form the above-mentioned input port arrangement, and port sensors 12, 12' are arranged at the ports P2, P2'. The port sensors 12, 12' may be seen to form the above-mentioned port sensor arrangement or part thereof. In the example of EIG. 4, the port sensor arrangement is configured to detect when the terminal connectors 8a, 8a' are attached to and / or disconnected from the ports P2, P2' and / or detect that an inlet opening of the input port arrangement is closed off after disconnection of a terminal connector 8a, 8a', for example by detecting presence or absence of a cover (cf. lid 71 in EIGS 10A-10B).

[0082] As shown in EIG. 4A, the main line LI extends from the valve V4 through a 3- way valve V5, which is operable to admit the first concentrate into the main line LI, and a 3 -way valve V6, which operable to admit the second concentrate into the main line LI. A pressure sensor SI is arranged intermediate the valves V5, V6. The signal from the pressure sensor SI may be used in state I to provide pressure feedback for controlling the fluid pressure between the valves V5, V6 to a stable value. The fluid pressure at SI may be stabilized by operating a control element in the source 5 to stabilize the pressure of the product water in the circulation line 50. Instabilities in fluid pressure at SI may impact the concentrate dosing and hence the composition of the treatment fluid. Eirst and second mixing chambers 13, 14 are arranged in the main line LI downstream of the valve V6. The first mixing chamber 13 is a high- swirl chamber configured to even out any large concentration / density differences that may be caused by the entry of concentrates. The use of two mixing chambers 13, 14 in series is a design option which has been found to promote efficient mixing of product water and concentrates. Thus, downstream of the second mixing chamber 14, the product water and the concentrates have been mixed to form the treatment fluid. It is realized that the above-mentioned mixing arrangement (11 in FIGS 1B-1C) includes the mixing chambers 13, 14 in the specific example of FIGS 4A-4B. Intermediate the mixing chambers 13, 14, a heater 9 is arranged. The heater 9 may be an electrical heater or any other type of device capable of heating a passing fluid. Temperature sensors S2, S3 are arranged in the main line LI to sense the fluid temperature upstream and downstream of the heater 9. During production, the heater 9 may be operated by feedback control, based on a signal from the sensor S3, to control the downstream fluid temperature to a predefined temperature, for example 37 °C. A 3-way valve V7 is arranged in the main line LI downstream of the second mixing chamber 14. The valve V7 is connected to a gas removal line L7, which is connected to a top portion of the mixing chamber 14. The valve V7 is operable to selectively connect the gas removal line L7 to the main line LI, for example to release gases accumulated in the second mixing chamber 14 during production of treatment fluid. A main fluid pump FP1 is arranged in the main line LI downstream of the valve V7. The main fluid pump FP1 sets the flow rate of treatment fluid along the main line 1 to the supply port Plb. Downstream of the fluid pump FP1, a pressure sensor S4, a conductivity sensor S5, and a temperature sensor S6 are arranged in the main line LI. The conductivity sensor S5 may be used to provide conductivity feedback when treatment fluid is generated, as well as during phases when the mixture of product water and concentrates is not delivered through the supply port Plb, for example during composition stabilization before start of an FGS. The signal from the temperature sensor S6 may be used for temperature compensation of the signal from the conductivity sensor S5, as is well-known in the art.

[0083] Turning now to FIG. 4B, a 3-way valve V8 is arranged in the main line LI downstream of the conductivity sensor S5. The valve V8 is connected to an intermediate line L13, which extends to a junction J5 on a drain line L3. The valve V8 is operable to selectively connect the main line LI to the drain line L3. A 3-way valve V9 is arranged in the main line LI downstream of the valve V8. The valve V9 is connected to a terminal line L9 that extends to a microbial-retentive air filter 15. The valve V9 is operable to selectively connect the main line LI to the air filter 15, for example when the FPS 10 is operated to draw in air for testing the integrity of the ultrafilters UF1, UF2. The integrity test is not relevant for the present disclosure and will not be described herein. A first ultrafilter UF1 is arranged downstream of the valve V9 in the main line LI. Inside UF1, a filter membrane (not shown) is arranged to separate a lumen side (feed side) from a filtrate side (permeate side). UF1 is interposed in the main line LI, so that in the flow path along the main line LI passes the filter membrane. A second ultrafilter UF2 is similarly arranged in series with UF1 along the main line LI. An on / off valve V10 is arranged in the main line LI between UF1 and UF2. A pressure sensor S7 is arranged in the main line LI downstream of UF2. The sensor S7 is mainly used for monitoring fluid pressure during the above-mentioned integrity test. A 3- way valve VI 1 is arranged in the main line LI between UF2 and the supply port Plb. The valve VI 1 is connected to a return line L6, which extends back to the valve V4 (FIG. 4A). The valve VI 1 is operable to divert an incoming flow on the main line LI into the return line L6, and the valve V4 is operable to selectively admit fluid from the return line L6 into the main line LI.

[0084] The FPS 10 further comprises a return port P4a for receipt of spent treatment fluid. A drain line L4 extends from the port P4a to a second drain port P4b. Further, a connecting line L12 extends between the supply port Plb and the return port P4a. The connecting line L12 enables the terminal end of the main line LI and the supply port Plb to be disinfected. In this respect, L12 performs the same function as AL1 in FIG. 3. It is realized that L12 additionally enables disinfection of P4a and L4.

[0085] In the illustrated example, the FPS 10 includes additional fluid lines and valves that are used for enabling flushing of the lumen side of UF1 and UF2. Specifically, a fluid line LI 1 is connected to the lumen side of UF1 and extends to a junction J3 on the return line L6, and a fluid line L10 is connected to the lumen side of UF2 and extends to a junction J2 in fluid line LI 1. An on / off valve V 12 is arranged in the fluid line Li l between UF1 and the junction J2, and an on / off valve V13 is arranged in the fluid line Li l between junctions J2, J3. Further, the drain line L3 extends from a junction J4 in the return line L6 to the drain port P3, and a respective on / off valve V16, V17 is arranged in the drain line L3 between the junctions J4, J5 and between the junction J5 and the drain port P3.

[0086] The return line L6 includes an on / off valve V14 between the valve VI 1 and the junction J3, and an on / off valve 15 between the junction J4 and the valve V4 (FIG. 4A). In the illustrated example, the return line L6 is further arranged to extend through rinse channels in the fluid pumps FP1, FP2, FP3 (FIG. 4A).

[0087] Reverting to FIG. 4A, the fluid line L5 extends from the connection point Cl to a junction JI on the return line L6. A 3-way valve V2 is arranged in the fluid line L5 and connected to an intermediate or auxiliary line L8, which extends to the concentrate port P2. A 3-way valve V3 is arranged in the fluid line L5 and connected to an intermediate or auxiliary line L8', which extends to the concentrate port P2'. With reference to FIG. 3, L8 and L8' may correspond to AL2. Further, an on / off valve VI is arranged in the fluid line L5 intermediate the valve V3 and the junction JI. The fluid line L5' extends from the connection point C2 to the valve V4, which is operable to selectively establish fluid communication between the main line LI and one of the fluid line L5' or the return line L6.

[0088] The 3-way valves in FIGS 4A-4B are of different types depending on desired functionality. FIGS 4C-4D are schematic drawings of two different types of 3-way valves Vx, Vy. Each valve has three valve portions (represented by triangles) which jointly define an internal valve chamber (not shown). The valve portions are connected to a respective fluid line La, Lb, Lc. Valve seats inside the valve portions are designated VS and indicated by an open circle. It is understood that a moveable element (plunger or the like, not shown) is arranged in the valve for engagement with the valve seat VS to close a passage defined by the valve seat VS.

[0089] The valve Vx in EIG. 4C has a single valve seat VS in the valve portion that is connected to line Lc and is always open between lines La and Lb. The valve Vx is operable to selectively open fluid communication with line Lc. The valve Vx is installed as valves V2, V3, V5, V6, Vl l in EIGS 4A-4B. The valve Vx has the specific advantage of facilitating heat disinfection of the internal valve chamber of the valve Vx via La and Lb.

[0090] The valve Vy in EIG. 4D has two valve seats VS in the valve portions that are connected to lines La and Lb. The valve Vy is operable to selectively open fluid communication between lines La and Lc, or between lines Lb and Lc. The valve Vy is installed as valves V4, V7, V8, V9 in EIGS 4A-4B.

[0091] In the following, the operation of the EPS 10 of EIGS 4A-4B in the different states I-V will be exemplified with reference to EIGS 5-9. Lor clarity of presentation, operating fluid pumps and open valve portions are indicated by filled triangles. It is to be understood that a valve portion is permanently open if it lacks a valve seat. Also, a valve portion with a valve seat may be either normally open or normally closed. Further, fluid lines through which fluid is flowing are indicated by thicker lines. The flow direction is indicated by solid arrows. In some contexts, the valves in the FPS 10 are collectively referred to as a "valve arrangement" or "valve sub-system".

[0092] FIGS 5A-5B show the FPS 10 in state I, during fluid generation. The source 5 is operated to continuously pump product water through the circulation line 50. All fluid pumps FP1, FP2, FP3 are operating to pump product water, the first concentrate and the second concentrate through the FPS 10. Valves V2, V3 are closed, valve VI is open, valve V15 is closed (FIG. 5B), and valve V4 fluidly connects the fluid line L6 to the main line LI. Thereby, product water is pumped by FP1 from the connection point Cl through fluid line L5 into fluid line L6, and from fluid line L6 into the main line LI. Valve V5 is open, so that FP2 pumps the first concentrate from the container 7 through the inlet line L2 into the main line LI. Similarly, valve V6 is open, so that FP3 pumps the second concentrate from the container 7' through inlet line L2' into the main line LI. Valve V7 is open to the main line LI and closed to the gas removal line L7. Thereby, the combination of product water and concentrates flow through the first and second mixing chambers 13, 14 to form the treatment fluid. The speed of FP1 sets the flow rate of treatment fluid through the main line LI. The speeds of FP2 and FP3 are set in relation to the speed of FP1 to achieve a target composition of the treatment fluid. The composition of the treatment fluid may be intermittently or continuously monitored by use of the conductivity sensor S5. The heater 9 may be operated to achieve a predefined target temperate of the treatment fluid. Downstream of FP1, as shown in FIG. 5B, valves V8, V9, V10, VI 1 are operated to open the main line LI, while the valves V 12, V13 are closed, so that the treatment fluid is directed through the ultrafilters UF1, UF2 and is supplied via the supply port Plb, which is connected to a receiving device (not shown, cf. connector 21a in FIG. 3). The supply port Plb may be configured to automatically open a passage between the main line LI and the connecting line L12 when the port Plb is disconnected, and automatically prevent fluid communication with the connecting line L12 when the port Plb is connected to the receiving device.

[0093] As will be shown below with reference to FIG. 6, the remaining subset includes the fluid lines L2, L2', L8, L8'. It may be noted in FIG. 5A that part of the remaining subset, namely the fluid lines L2, L2', is inherently flushed or primed with concentrate during fluid production.

[0094] As is well-known to the skilled person, the FPS 10 may be operated in a setup state (not shown) to determine speed ratios between the fluid pumps FP1, FP2, FP3 to achieve the target composition of the treatment fluid. In one example of the setup state, FP1 and FP2 are first operated, and the valve arrangement is operated to admit product water and first concentrate into the main line LI. FP1 may be operated at a speed resulting in a target flow rate to be used in the fluid generation (state I). The speed of FP2 is adjusted to attain a first predefined conductivity at the sensor S5. Then, FP3 is started and the valve arrangement is operated to also admit second concentrate into the main line LI. The speed of FP3 is adjusted to attain a second predefined conductivity at the sensor S5, where the second predefined conductivity corresponds to the target composition of the treatment fluid. During the setup state, the valve arrangement is operated to direct the fluid from the main line LI to drain, via fluid lines L13 and L3. When the target composition is attained, the FPS 10 may be switched to fluid generation (state I) by operating the valve arrangement to direct the treatment fluid through the main line LI to the supply port Plb, as shown in FIGS 5A-5B. FIG. 6 shows the FPS 10 in a sub-state IIx during the first heat disinfection (state II). As a result of the large number of interconnected fluid lines in the fluid path arrangement within the FPS 10, the first heat disinfection will be performed by operating the valve arrangement to direct heated fluid on different paths through the FPS 10. Each such path corresponds to a sub-state of state II. Some of the paths may involve a circulation of heated fluid through the FPS 10, while other paths may involve a one-way path through the FPS 10 to the drain. The exact details of the different substates are not relevant to the present disclosure and will not be described. However, it should be noted that the inlet lines L2, L2' and the intermediate lines L8, L8' will not be disinfected while the containers 7, 7' are connected to the concentrate ports P2, P2'. Thus, the lines L2, L2', L8, L8', and the fluid pumps FP2, FP3 therein, form the above- mentioned remaining subset that is heat disinfected in the second heat disinfection (state IV), together with the ports P2, P2'.

[0095] For context only, sub- state IIx in FIG. 6 will be briefly described. The sub- state IIx is typically the final sub-state during the first heat disinfection and involves disinfecting the connection points Cl, C2. During sub-state IIx, the source 5 is operated to stop the flow of product water through the circulation line 50. The fluid pump FP1 is operating to pump product water through the FPS 10, whereas fluid pumps FP2, FP3 are stopped. Valves V2, V3, V5, V6 are closed to seal off the remaining subset. The valve arrangement is operated to define a recirculation path in the FPS 10 that includes the connection points Cl, C2. In the illustrated example, valve V4 fluidly connects the fluid line L5' to the main line LI, valve V7 is open to the main line LI and closed to the gas removal line L7, valve V8 closes the main line LI and is open to the intermediate line L13, valves V15, V16 are open, valves V14, V17 are closed, and valve VI is open.

[0096] During the circulation of the product water, the heater 9 is operated to heat the passing product water. The required duration of the recirculation to achieve a sufficient microbial deactivation is a function of the fluid temperature. It is currently believed that the fluid temperature should be measured at the coldest spot in the flow path to be disinfected. In the example of EIG. 6, the coldest spot is immediately upstream of the heater 9, at the temperature sensor S2. In some embodiments, the required duration may be determined based on the A0 concept, where the A0 value is determined based on the measured temperature by the sensor S2.

[0097] EIG. 7 shows the EPS 10 in a sub-state IVx during the second heat disinfection (state IV). The sub-state IVx is performed to heat disinfect the remaining subset, including the fluid lines L2, L2', L8, L8' and the fluid pumps LP2, LP3 therein, as well as the ports P2, P2' that are connected to the remaining subset. As seen, the second heat disinfection is performed when the ports P2, P2' have been disconnected from the containers 7, 7', and a passage is defined inside the respective port P2, P2' between the lines L8, L2 and L8', L2'. The respective port P2, P2' may be configured to automatically define the passage when the port P2, P2' is disconnected. In one example, the concentrate port P2 (or P2') is configured to allow a fluid flow between the auxiliary line L8 (or L8') and the inlet line L2 (or L2') when the port P2 (or P2') is disconnected and closed, typically closed by a lid (not shown). The fluid flow may then flow over the outer part of port P2 (or P2') to disinfect it, i.e., to perform a port disinfection. An example of such a port is shown in FIGS 10A-10B and described further below.

[0098] State IV may include further sub- states if other fluid path of the FPS 10 are to be heat disinfected in the second heat disinfection. In some embodiments, to disinfect the entire fluid path arrangement in the FPS 10, the second heat disinfection also involves all sub- states of the first heat disinfection (state II).

[0099] In sub- state IVx, the valve arrangement is operated to define a recirculation path in the FPS 10 that includes the fluid lines L2, L2', L8, L8', and the fluid pumps FP1, FP2, FP3 are operated to circulate product water in the recirculation path. Sub-state IVx, as shown, thus presumes that the recirculation path has been previously primed with product water. During the circulation of the product water, the heater 9 is operated to heat the passing product water. Like in the first heat disinfection, the duration of the circulation may be determined by an A0 value given as a function of the measured temperature by the sensor S2.

[0100] In the example of FIG. 7, to achieve the recirculation path, the source 5 is operated to stop the flow of product water through the circulation line 50, the valves V2, V3, V5, V6 are open, valve V4 fluidly connects the fluid line L6 to the main line LI, valve V7 is open to the main line LI and closed to the gas removal line L7, valve V8 closes the main line LI and is open to the intermediate line L13, valves V15, V16 are open, valves V14, V17 are closed, and valve VI is open. By operating all fluid pumps FP1, FP2, FP3, product water is circulated along the main line LI to the valve V8 and into the intermediate line LI 3, from the intermediate line LI 3 into the drain line L3 between junctions J5 and J4, and into the return line L6 between junctions J4 and JI. At junction J 1 , the flow of product water is split into a first sub-path that extends along the return line L6 to the valve V4 and into the main line LI, and a second sub-path that extends along the fluid line L5 to valves V2 and V3, where the flow is bifurcated into a first flow through the fluid line L8', the port P2', the fluid line L2' to the valve V6 and into the main line LI, and a second flow through the fluid line L8, the port P2, the fluid line L2 to the valve V5 and into the main line LI.

[0101] In a variant of FIG. 7, the source 5 is operated to circulate the product water through the circulation line 50 in sub-state IVx. In such a variant, the source 5 may be operated to generate an overpressure that is exerted onto the FPS 10 to prevent product water from flowing from the FPS 10, on fluid line L5, back to the circulation line 50 and into the source 5.

[0102] FIGS 8A-8B show the FPS 10 in two sub-states during a concentrate priming of the remaining subset. In the illustrated example, the remaining subset may be seen to include a first partition, given by L2, L8, which is associated with the first container 7, and a second partition, given by L2', L8', which is associated with the second container 7'. The states in FIGS 8A-8B are attained to fill the first partition with first concentrate. Corresponding sub-states for filling the second partition with the second concentrate are not shown but are defined by analogy with FIGS 8A-8B. As indicated by dashed circles, FIGS 8A-8B may be seen to represent sub-states Va, Vb of the preparatory priming state V, or sub-states Illa, Illb of the intermittent priming state III. For simplicity of notation, the sub-states in FIGS 8A-8B are referred to as Va, Vb in the following.

[0103] In sub- state Va, a first flow path is established from the concentrate port P2 to the drain port P3. The first flow path includes the inlet line L2. Although not shown in FIGS 8A-8B, the drain port P3 is connected to a tubing that extends to drain (cf. FIG. IB). The fluid pumps FP1 and FP2 are operated to draw first concentrate into the first flow path to prime the inlet line L2 with first concentrate. The fluid pumps FP1, FP2 may be operated for a predefined time, which is known to result in the adequate priming of the inlet line L2. Alternatively, the pumps FP1, FP2 may be stopped when the conductivity sensor S5 detects a conductivity representative of the first concentrate.

[0104] After sub-state Va, the FPS 10 is switched to sub-state Vb, in which a second flow path that includes the intermediate line L8 is established from the concentrate port P2 to the drain port P3. The fluid pump FP1 is operated to draw the first concentrate into the second flow path to prime the intermediate line L8 with first concentrate. The fluid pump FP1 may be operated for a predefined time, which is known to result in the adequate priming of the intermediate line L8.

[0105] In FIGS 8A-8B, the first and second flow paths are established to not include the connection points Cl, C2 since it is undesirable to pump concentrate into the circulation line 50 of the source 5. It is also to be noted that the order of the states Va and Vb may be reversed. One advantage of attaining Va before Vb is that state Va enables initial checking of the conductivity of the concentrate, by use of the sensor S5, without having to direct concentrate through fluid lines that otherwise do not carry concentrate. State Va leads concentrate via the inlet line L2 and the main line LI through the sensor S5. If the concentrate does not have a correct conductivity, the FPS 10 may instruct the user to change the container 7, whereupon state Va is continued when the container 7 has been changed. Then, when the FPS 10 has switched to state Vb, only a small portion of concentrate needs to enter the FPS 10 to fill the intermediate line L8.

[0106] However, it is also conceivable to perform a check of the conductivity of the respective concentrate during state I, for example by checking that a mixture of product water and one or more concentrates has a conductivity, given by sensor S5, that lies in an acceptable range.

[0107] In FIG. 8A, to establish the first flow path, the source 5 is operated to stop the flow of product water through the circulation line 50, valves VI, V2, V3 are closed, valve V4 fluidly connects the fluid line L6 to the main line LI, valve V7 is open to the main line LI and closed to the gas removal line L7, valve V8 closes the main line LI and is open to the intermediate line L13, valves V15, V16 are closed and valve V17 is open. By operating fluid pumps FP1, FP2, first concentrate is drawn via the concentrate port P2 through the inlet line L2 and the main line LI to the valve V8, which diverts the flow into the intermediate line L13, which directs the flow into the drain line L3 and through the drain port P3. The operation of the pumps FP1, FP2 may be controlled to achieve a predefined pressure at the sensor SI.

[0108] In FIG. 8B, to establish the second flow path, valves V 1, V2 are open, valves V3, V5, V6 are closed, valve V4 fluidly connects the return line L6 to the main line LI, valve V7 is open to the main line LI and closed to the gas removal line L7, valve V8 closes the main line LI and is open to the intermediate line L13, valves V15,V16 are closed and valve V17 is open. By operating the fluid pump FP1, first concentrate is drawn via the concentrate port P2 through the intermediate line L8, the fluid line L5 and the fluid line L6 to valve V4, which diverts the flow into the main line LI, from where the flow is directed through the drain port P3 in the same way as in state Va.

[0109] FIGS 9A-9C show an FPS 10 with an alternative construction. The difference compared to the FPS 10 of FIGS 4A-4B is that an additional 3-way valve VI 8, VI 8' is arranged in the respective inlet line L2, L2' and is connected to a respective intermediate fluid line L14, L14', which extends to a respective junction J6, J6' on the fluid line L5. The valves VI 8, VI 8' are of the type shown in FIG. 4D. To the extent that portions of the FPS 10 are not shown in FIGS 9A-9C, they are identical to the FPS 10 in FIGS 4A- 4B

[0110] One reason for the alternative construction in FIGS 9A-9C is to improve the operational reliability of the FPS 10. In the example of FIGS 8A-8B, the fluid pumps FP2, FP3 are included in the remaining subset and are thus filled with concentrate in state III / V. The concentrate then resides in the fluid pumps FP2, FP3 until the FPS 10 is again operated for fluid generation (state I). There is a risk the fluid pumps FP2, FP3 get stuck if they are not operated for a prolonged time while they are exposed to concentrate. The risk for pump sticking may differ between concentrates. The FPS 10 in FIGS 9A-9C is configured to locate the fluid pumps FP2, FP3 outside of the remaining subset, thereby minimizing the risk for pump sticking.

[0111] FIGS 9A-9B show the FPS 10 in sub-states during the concentrate priming of the remaining subset. In the illustrated example, the remaining subset may be seen to include a first partition, given by L8 and an upstream portion of L2 that extends between the port P2 and the valve VI 8, and a second partition, given by L8' and an upstream portion of L2' that extends between the port P2' and the valve VI 8'. The states in FIGS 9A-9B are attained to fill the first partition with first concentrate. Corresponding sub-states for filling the second partition with the second concentrate are not shown but are defined by analogy with FIGS 9A-9B.

[0112] Like in FIGS 8A-8B, FIGS 9A-9B may be seen to represent sub-states Va, Vb of the preparatory priming state V, or sub-states Illa, Illb of the intermittent priming state III. Again, for simplicity of notation, the sub-states in FIGS 9A-9B are referred to as Va, Vb in the following.

[0113] In sub- state Va, a first flow path is established from the concentrate port P2 to the drain port P3. The first flow path includes the inlet line L2. The fluid pumps FP1 (not shown) and FP2 are operated, by analogy with FIG. 8A, to draw first concentrate into the first flow path to prime the inlet line L2 with first concentrate.

[0114] After sub-state Va, the FPS 10 is switched to sub-state Vb, in which a second flow path that includes the intermediate line L8 is established from the concentrate port P2 to the drain port P3. The fluid pump FP1 is operated, by analogy with FIG. 8B, to draw first concentrate into the second flow path to prime the intermediate line L8 with first concentrate.

[0115] FIG. 9C shows the alternative FPS 10 of FIGS 9A-9B during the first heat disinfection (state II), in a sub-state Ily. Like the sub-state IIx in FIG. 6, the sub-state Ily may be the final sub-state during the first heat disinfection. In sub-state Ily, the source 5 is operated to stop the flow of product water through the circulation line 50. The fluid pumps FP1, FP2, FP3 are operating to pump product water through the FPS 10. Valves V2, V3 are closed, and valves V18, V18' are closed towards the ports P2, P2' to seal off the remaining subset. The valve arrangement is operated to define a recirculation path in the FPS 10 that includes the connection points Cl, C2. In the illustrated example, valve V4 fluidly connects the fluid line L5' to the main line LI, valves V5, V6 are open to the inlet lines L2, L2', valve V7 is open to the main line LI and closed to the gas removal line L7, valve V8 closes the main line LI and is open to the intermediate line L13, valves V15, V16 are open, valve V17 is closed, and valve VI is open. Although not shown in FIG. 9C, valve V14 in the return line L6 is closed. During the circulation of the product water along the recirculation path, the heater 9 is operated to heat the passing product water. Like in FIG. 6, the duration of the circulation may be determined by an AO value given as a function of the measured temperature by the sensor S2.

[0116] The configurations of the FPS 10 in FIGS 8-9 are merely given as non-limiting examples and countless variations are possible.

[0117] FIGS 8-9 may be seen to represent an embodiment of an FPS 10, in which the remaining subset comprises an inlet line L2 that extends from a port P2 in an input port arrangement of the FPS 10 and is arranged for fluid communication with a concentrate pump FP2, and an auxiliary line L8 that extends from the port P2 and is arranged for fluid communication with a further fluid pump FPL In this embodiment, the FPS 10 may be operated to perform a priming operation, which comprises: a first step of priming the inlet line L2 by operating the concentrate pump FP2 to draw concentrate via the port P2 through the inlet line L2, and by operating a valve arrangement in the FPS 10 to close the inlet line L2; and a second step of priming the auxiliary line L8 by operating the valve arrangement to open fluid communication between the port P2 and the further fluid pump FP1 via the auxiliary line L8, operating the further fluid pump FP1 to draw the concentrate via the port P2 through the auxiliary line L8, and operating the valve arrangement to close the auxiliary line L8. The first and second steps may be performed in any order. This priming operation provides the advantage of filling the remaining subset with concentrate in a robust and simple way.

[0118] FIGS 8-9 may also be seen to represent an embodiment of an FPS 10, in which the remaining subset comprises an inlet line L2 that extends from a port P2 in an input port arrangement of the FPS 10 and is arranged for fluid communication with a concentrate pump FP2, and an auxiliary line L8 that extends from the port P2 and is arranged for fluid communication with a further fluid pump FP1, and in which a fluid path arrangement in the FPS 10 comprises a valve arrangement which is operable to selectively open and close the inlet line L2 and to selectively open and close fluid communication between the port P2 and the further fluid pump FP1 via the auxiliary line L8. By such a valve arrangement, the remaining subset may be simply and efficiently filled with concentrate by proper control of the fluid pumps and the valve arrangement.

[0119] Further, FIGS 9A-9C may be seen to represent an embodiment, in which the valve arrangement comprises a control valve VI 8, which is located in the inlet line L2 intermediate the port P2 and the concentrate pump FP2. By such a control valve VI 8, it is possible to locate the concentrate pump FP2 outside the remaining subset, which means that the concentrate pump FP2 need not be filled with concentrate but will be subjected to heated fluid during the first heat disinfection. Thus, in this embodiment, the first heat disinfection may be performed to heat disinfect the inlet line L2 downstream of the control valve VI 8. In some embodiments, the control valve VI 8 may be operable to block the inlet line L2 on a first side of the valve VI 8 facing towards the port P2 while opening a fluid path between a connecting line L14 and the inlet line L2 on a second side of the valve VI 8 facing towards the concentrate pump FP2. This allows for the second side of valve VI 8 to be heat disinfected via the connecting line L14 and the downstream portion of the inlet line L2 during the first heat disinfection (state II), as shown in FIG. 9C.

[0120] FIGS 10A-10B are section views of an example concentrate port P2 as installed in an FPS. FIG. 10A depicts a connected state, in which the port P2 is connected to the terminal connector 8a on the disposable tubing 8. FIG. 10B depicts a disconnected state, in which the port P2 is closed off and thus disconnected from the disposable tubing 8. The port P2 comprises a main body 70 and a lid or cap 71, which is joined to the main body 70 for rotation around a hinge 72. The main body 70 defines a cavity or hole 73. The cavity 73 defines an opening for receiving the connector 8 a. The inlet line L2 opens into the internal cavity 73. The auxiliary line L8 opens into the cavity 73 at its perimeter. In the connected state, FIG. 10A, the lid 71 is swung away from the main body 70 to expose the opening to the cavity 73, and the connector 8a is engaged with the opening. Thereby, the tubing 8 is in fluid communication with the inlet line L2 and the auxiliary line L8 via the cavity 73. In the disconnected state, FIG. 10B, the lid 71 is swung into contact with the main body 70 so that a recess 74 in the lid 71 mates with the opening to the cavity 74. The cavity 73 and the recess 74 thereby defines an internal chamber, which is closed to the surroundings and directs incoming fluid to pass from the auxiliary line L8 to the inlet line L2, and vice versa. The lid 71 may be biased towards the main body 70, so that the port P2 is automatically brought into the state in FIG. 10B when the terminal connector 8 is disengaged from the cavity 73. With reference to FIG. 7, it is realized that the FPS 10 is configured to heat disinfect not only the inlet line L2 and the auxiliary line L8, but also the internal chamber of the port P2 during the second heat disinfection (state IV).

[0121] The port P2' may be configured in correspondence with FIGS 10A-10B.

[0122] FIG. 11 is a block diagram of an example control arrangement or sub-system 80, which may be configured to control the operation of the FPS 10, and optionally the source 5 and / or the therapy system 20. The functionality of the control arrangement 80 may be defined by a combination of software and hardware circuitry, or exclusively by specific hardware circuitry. In FIG. 11, the control arrangement 80 comprises processor circuitry 81, which may be or include a central processing unit (CPU), graphics processing unit (GPU), microcontroller, microprocessor, ASIC, FPGA, or any other specific or general processing device. The control arrangement 80 may operate by executing instructions stored in a computer memory, such as memory 82. The instructions when executed by the processor circuitry 81 may cause the control arrangement 80 to perform any of the methods, procedures and functions described herein, or part thereof. The memory 82 may comprise one or more of a buffer, flash memory, hard drive, removable media, volatile memory, non-volatile memory, random access memory (RAM), or another suitable data storage device. Such a memory 82 is considered a non-transitory computer readable medium. The instructions may be supplied to the control arrangement 80 on a computer-readable medium, which may be a tangible (non-transitory) product (for example magnetic medium, optical disk, readonly memory, flash memory, etc.) or a propagating signal. The control arrangement 80 includes an I / O interface 83a, which may include any conventional communication interface for wired or wireless communication. As shown, the control arrangement 80 is arranged to receive input signals Si and to output control signals Cj. For example, the input signals may be obtained from the sensors S1-S6 and the port sensors 12, 12' in the FPS 10, and the control signals may be provided to the valves VI- VI 8 and the fluid pumps FP1-FP3. The control arrangement 80 may comprise a further interface 83b for connection to a feedback device 84 for user interaction. The feedback device 84 may include one or more of a display, a touch screen, a speaker, one or more signaling lamps, a keyboard / keypad, a microphone, a computer mouse, a projector, a camera, etc.

[0123] Below follows a list of some components in the FPS 10 of FIGS 4A-4B and a non-limiting description of their respective purpose / function.

[0124] 9 [heater]: used for controlling fluid temperature in the FPS 10 during fluid generation (state I) and heat disinfection (states II, IV).

[0125] 13 [first mixing chamber]: used for reducing concentration / density differences present after dosing of the first and second concentrates into the main line LI.

[0126] 14 [second mixing chamber]: used for achieving a sufficient mixing to provide a stable conductivity measurement by the conductivity sensor S5.

[0127] FP1 [main fluid pump]: operated for driving fluid flow through the main line LI during fluid generation (state I), during heat disinfection (states II, IV), and during concentrate priming (states III, V).

[0128] FP2 [concentrate pump]: operated for dosing of the first concentrate during fluid generation (state I), for driving heated fluid during heat disinfection (states II, IV) and for in-feed of the first concentrate during concentrate priming (states III, V). FP3 [concentrate pump]: operated for dosing of the second concentrate during fluid generation (state I), for driving heated fluid during heat disinfection (states II, IV), and for in-feed of the second concentrate during concentrate priming (states III, V).

[0129] 51 [pressure sensor]: used during fluid generation (state I) for monitoring fluid pressure at point of entry of the first and second concentrates into the main line LI, as well as for pressure control feedback and optionally for pressure compensation of the mixing mechanism.

[0130] 52 [temperature sensor]: used for monitoring fluid temperature upstream of the heater 9, at the anticipated coldest point in the fluid path arrangement when heated fluid in circulated in the FPS 10 during heat disinfection (states II, IV), and optionally for feedforward control of the heater 9 during heat disinfection (states II, IV).

[0131] 53 [temperature sensor]: used for sensing fluid temperature downstream of the heater 9 for feedback control of the heater 9 during fluid generation (state I) and heat disinfection (states II, IV).

[0132] 54 [pressure sensor]: used for monitoring pressure pulsations caused by FP1 for overheat protection purposes and also to detect elevated counter-pressure caused by malfunctions downstream along the main line LI, for example clogging of UF1 or UF2.

[0133] 55 [conductivity sensor]: used for conductivity feedback during a setup state for determination of pump speed ratios between FP1, FP2 and FP3, and for conductivity checks during fluid generation (state I).

[0134] S7 [pressure sensor]: used for sensing fluid pressure during ultrafilter integrity test and to detect obstructions downstream the supply port Plb.

[0135] VI [on / off valve]: used for preventing pressure in the source 5 to build up in the FPS 10 when idle, which may, e.g., cause rinse channel leakage to surroundings in FP1, FP2 and FP3.

[0136] V2 [3-way valve]: used for enabling a heat disinfection loop through the concentrate port P2 and the inlet line L2 when the container 7 has been detached from the concentrate port P2.

[0137] V3 [3-way valve]: used for enabling a heat disinfection loop through the concentrate port P2' and the inlet line L2' when the container 7' has been detached from the concentrate port P2'.

[0138] V4 [3-way valve]: used for directing product water into the main line LI during fluid generation (state I) and heat disinfection (states II, IV), and for including the main line LI in a recirculation path during heat disinfection (states II, IV).

[0139] V5 [3-way valve]: used for closing the transition from the inlet line L2 to the main line LI whenever the first concentrate is not dosed into the main line LI, so as to prevent the first concentrate in the inlet line L2 from being diluted, which would compromise the effectiveness of the first concentrate to mitigate microbial growth in the inlet line L2 (states III, V).

[0140] V6 [3-way valve]: used for closing the transition from the inlet line L2' to the main line LI whenever the second concentrate is not dosed to the main line LI, so as to prevent the second concentrate in the inlet line L2' from being diluted, which would compromise the effectiveness of states III and V to mitigate microbial growth in the inlet line L2' (states III, V).

[0141] V7 [3-way valve]: used for allowing FP1 to draw fluid from two different outlet ports on the second mixing chamber 14, either a top port during degassing or a bottom port during fluid generation.

[0142] V8 [3-way valve]: used for directing fluid to drain during composition stabilization (cf. setup state, above), during concentrate priming (states III, V), and during heat disinfection (states II, IV), as well as to direct gases evacuated from the second mixing chamber 15 to drain without being passed to UF1 and UF2.

[0143] V9 [3-way valve]: used for supplying UF1 and UF2 either with fluid from the main line LI, or air from the air filter 15.

[0144] V10 [on / off valve]: used for stopping fluid flow to the filtrate side of UF1 during flushing of the lumen side of UF1.

[0145] VI 1 [3-way valve]: used for allowing or prohibiting delivery of treatment fluid via the supply port Plb during fluid generation (state I).

[0146] V 12 [on / off valve]: used for opening a flush path on the lumen side of UF1 for cleaning of UF1 and for closing the flush path of UF1 during fluid generation (state I).

[0147] V13 [on / off valve]: used for opening a flush path on the lumen side of UF2 for cleaning of UF2 and for closing the flush path of UF2 during fluid generation (state I).

[0148] V14 [on / off valve]: used for directing gas or fluid to drain during priming of UF1 and UF2.

[0149] V15 [on / off valve]: used for enabling recirculation during heat disinfection (states II, IV).

[0150] V16 [on / off valve]: used for, together with valve V17, directing fluid downstream of UF1 and UF2 to drain.

[0151] V 17 [on / off valve]: used for opening up a path to drain to direct fluid upstream of or downstream of UF1 and UF2 to the drain.

[0152] While the subject of the present disclosure has been described in connection with what is presently considered to be the most practical embodiments, it is to be understood that the subject of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the appended claims.

[0153] Further, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.

[0154] In the following, clauses are recited to summarize some aspects and embodiments as disclosed in the foregoing.

[0155] Cl. A system for generating a treatment fluid for use in dialysis, said system comprising: a mixing arrangement (11), which is operable to mix water with one or more liquid concentrates to generate the treatment fluid; a fluid path arrangement (L) for directing the water and the one or more liquid concentrates to and through the mixing arrangement (11) and for directing the treatment fluid from the mixing arrangement (11) for use in dialysis; an input port arrangement (P2, P2') in fluid communication with the fluid path arrangement (L) and configured for releasable connection to a set of containers (7, 7') holding the one or more liquid concentrates; a heater (9); and a control arrangement (80) which is configured to: operate the system, by use of the mixing arrangement (11), to perform a sequence of time- separated sessions of generating the treatment fluid; operate the system, between the time- separated sessions and by use of the heater (9), to perform a first heat disinfection of the fluid path arrangement (L) except for a first subset (L2, AL2) of the fluid path arrangement (L) that is configured for fluid communication with the input port arrangement (P2, P2'); and operate the system to arrange at least one liquid concentrate among the one or more liquid concentrates in said first subset (L2, AL2) between the time- separated sessions.

[0156] C2. The system of Cl, wherein the control arrangement (80) is configured to arrange said at least one liquid concentrate in said first subset (L2, AL2) by operating the system to perform at least one priming operation in which said at least one liquid concentrate is supplied to said first subset (L2, AL2) via the input port arrangement (P2, P2').

[0157] C3. The system of Cl or C2, wherein the control arrangement (80) is configured to operate the system to perform the first heat disinfection while the input port arrangement (P2, P2') is connected to at least one container in the set of containers (7, 7'), wherein said at least one container holds said at least one liquid concentrate.

[0158] C4. The system of C2 and C3, wherein said at least one priming operation comprises a preparatory priming operation which is performed after a connection operation, in which said at least one container is connected to the input port arrangement (P2, P2'), and before start of said sequence of time- separated sessions of generating the treatment fluid.

[0159] C5. The system of C3 or C4, wherein the control arrangement (80) is further configured to, while said at least one container is disconnected from the input port arrangement (P2, P2'), operate the system to perform a second heat disinfection of at least the first subset (L2, AL2) of the fluid path arrangement (L), and the input port arrangement (P2, P2').

[0160] C6. The system of C5, wherein the second heat disinfection is performed to heat disinfect all fluid paths of the fluid path arrangement (L).

[0161] C7. The system of C5 or C6, wherein the input port arrangement (P2, P2') comprises a port sensor arrangement (12, 12'), which is configured to provide a sensor signal indicative of disconnection of said at least one container from the input port arrangement (P2, P2') and closing of the input port arrangement (P2, P2'), and wherein the control arrangement (80) is configured to operate the system to perform the second heat disinfection when the sensor signal indicates that the input port arrangement (P2, P2') is closed and disconnected from said at least one container.

[0162] C8. The system of any one of C3-C7, wherein the control arrangement (80) is configured to cause said at least one container to be disconnected from the input port arrangement (P2, P2') after the sequence of time- separated sessions, so that the input port arrangement (P2, P2') remains connected to said at least one container throughout said sequence of time- separated sessions.

[0163] C9. The system of any preceding clause, wherein said at least one liquid concentrate is bacteriostatic.

[0164] CIO. The system of any preceding clause, wherein the control arrangement (80) is configured to perform a dedicated action when a residence time of said at least one liquid concentrate in said first subset (L2, AL2) exceeds a predefined maximum time.

[0165] Cl 1. The system of CIO in combination with any one of C5-C7, wherein said dedicated action comprises: causing said at least one container to be disconnected from the input port arrangement (P2, P2') and operating the system to perform the second heat disinfection; or operating the system to perform an intermittent priming operation, in which said at least one liquid concentrate is supplied to said first subset (L2, AL2) via the input port arrangement (P2, P2').

[0166] C12. The system of any preceding clause, wherein the fluid path arrangement (L) consists of reusable components.

[0167] C13. The system of Cl 2, wherein control arrangement (80) is configured to operate the system to perform the sequence of time-separated sessions over an extended time period, and the reusable components are configured to be maintained in the system at least throughout the extended time period.

[0168] C14. The system of any preceding clause, wherein the control arrangement (80) is configured to, before the first heat disinfection, operate one or more valves (V2, V3, V5, V6, V18, V18') in the fluid path arrangement (L) to define the first subset (L2, AL2) within the fluid path arrangement (L).

[0169] C15. The system of any preceding clause, wherein the fluid path arrangement (L) consists of the first subset (L2, AL2) and a second subset (LI, AL1, L3, L4, L5, AL5), wherein control arrangement (80) is configured to operate the fluid path arrangement (L) to fluidly separate the first subset (L2, AL2) from the second subset (LI, AL1, L3, L4, L5, AL5) before the first heat disinfection.

[0170] C16. The system of C15, wherein the control arrangement (80), to perform the first heat disinfection, is configured to operate the heater (9) to heat a disinfection fluid and operate the fluid path arrangement (L) to distribute the thus-heated disinfection fluid within the second subset (LI, AL1, L3, L4, L5, AL5).

[0171] C17. The system of any preceding clause, wherein the time- separated sessions are separated by a respective time interval, and wherein the control arrangement (80) is configured to operate the system to arrange said at least one liquid concentrate in the first subset (L2, AL2) throughout the respective time interval.

[0172] Cl 8. The system of any preceding clause, wherein the control arrangement (80) is configured to operate the system to perform the sequence of time-separated sessions over a time period of at least 3 days, such as 3, 4, 5, 6 or 7 days.

[0173] Cl 9. The system of any preceding clause, wherein consecutive sessions in the sequence of time-separated sessions are separated by at least 4, 6, 8, 10 or 12 hours.

[0174] C20. The system of any preceding clause, wherein the control arrangement (80), to perform a respective session of generating the treatment fluid, is configured to operate the mixing arrangement (11) to mix the water with the one or more liquid concentrates.

[0175] C21. The system of any preceding clause, wherein said subset of the fluid path arrangement (L) comprises an inlet line (L2) that extends from a port (P2) in the input port arrangement (P2, P2') and is arranged for fluid communication with a concentrate pump (FP2), and an auxiliary line (L8) that extends from the port (P2) and is arranged for fluid communication with a fluid pump (FP1), wherein the control arrangement (80) is configured to, during said at least one priming operation, operate the concentrate pump (FP2) to draw a liquid concentrate via the port (P2) through the inlet line (L2); operate a valve arrangement to close the inlet line (L2); operate the valve arrangement to open fluid communication between the port (P2) and the fluid pump (FP1) via the auxiliary line (L8); operate the fluid pump (FP1) to draw the liquid concentrate via the port (P2) through the auxiliary line (L8); and operate the valve arrangement to close the auxiliary line (L8).

[0176] C22. The system of C21, wherein the valve arrangement comprises a control valve (VI 8), which is located in the inlet line (L2) intermediate the port (P2) and the concentrate pump (FP2).

[0177] C23. The system of C22, wherein the first heat disinfection is performed to heat disinfect the inlet line (L2) downstream of the control valve (VI 8).

[0178] C24. The system of C22 or C23, wherein the control valve (VI 8) is operable to block the inlet line (L2) on a first side of the control valve (VI 8) facing towards the port (P2) while opening a fluid path between a connecting line (LI 4) and the inlet line (L2) on a second side of the control valve (VI 8) facing towards the concentrate pump (FP2).

[0179] C25. The system of any one of C21-C24, wherein the input port arrangement (P2, P2') is configured to define an internal chamber (73, 74) in fluid communication with the fluid path arrangement (L) when said at least one container is disconnected from the input port arrangement (P2, P2') , and wherein the second heat disinfection is performed to heat disinfect the inlet line (L2), the internal chamber (73, 74), and the auxiliary line (L8).

[0180] C26. The system of any preceding clause, wherein the control arrangement (80) is configured to operate the system, by use of the mixing arrangement (11), to perform each of the time-separated sessions to generate treatment fluid for use in peritoneal dialysis.

[0181] C27. The system of C26, wherein said each of the time- separated sessions corresponds to a respective treatment session of said peritoneal dialysis, wherein the treatment fluid generated in said each of the time- separated sessions is consumed during the respective treatment session.

[0182] C28. The system of C27, wherein the respective treatment session comprises a plurality of fluid exchange cycles, each comprising a fill phase, a dwell phase and a drain phase.

[0183] C29. The system of any preceding clause, wherein the control arrangement (80) is configured to operate the system, by use of the mixing arrangement (11), to perform each of the time-separated sessions to generate treatment fluid for use in extracorporeal blood dialysis.

[0184] C30. A computer-implemented method of operating a system for generating a treatment fluid for use in dialysis, said method comprising: operating a mixing arrangement (11) in the system to perform time-separated sessions of generating the treatment fluid by mixing water with one or more liquid concentrates, wherein a fluid path arrangement (L) directs the water and the one or more liquid concentrates to and through the mixing arrangement (11), and directs the treatment fluid from the mixing arrangement (11) for use in dialysis, and wherein the one or more liquid concentrates are supplied via an input port arrangement (P2, P2') which is releasably connected to a set of containers (7, 7') that hold the one or more liquid concentrates; operating the system to, between the time-separated sessions and by use of a heater (9), perform a first heat disinfection of the fluid path arrangement (L) except for a first subset (L2, AL2) of the fluid path arrangement (L) that is in fluid communication with the input port arrangement (P2, P2'); and operating the system to arrange at least one liquid concentrate among the one or more liquid concentrates in said first subset (L2, AL2) between the time- separated sessions.

[0185] C31. A computer-readable medium comprising program instructions, which when executed by processor circuitry (81), causes the processor circuitry (81) to perform the method of C30.

[0186] C32. A system for generating a treatment fluid for use in dialysis, said system comprising: a mixing arrangement (11), which is operable to mix water with one or more liquid concentrates to generate the treatment fluid; a fluid path arrangement (L) for directing the water and the one or more liquid concentrates to and through the mixing arrangement (11) and for directing the treatment fluid from the mixing arrangement (11) for use in dialysis; an input port arrangement (P2, P2') in fluid communication with the fluid path arrangement (L) and configured for releasable connection to a set of containers (7, 7') holding the one or more liquid concentrates; wherein the fluid path arrangement comprises an inlet line (L2) that extends from a port (P2) in the input port arrangement (P2, P2') and is arranged for fluid communication with a concentrate pump (FP2), and an auxiliary line (L8) that extends from the port (P2) and is arranged for fluid communication with a fluid pump (FP1); and wherein the fluid path arrangement further comprises a valve arrangement which is operable to selectively open and close the inlet line (L2) and selectively open and close fluid communication between the port (P2) and the fluid pump (FP1) via the auxiliary line (L8).

[0187] C33. The system of C32, wherein the valve arrangement comprises a control valve (VI 8), which is located in the inlet line (L2) intermediate the port (P2) and the concentrate pump (FP2).

[0188] C34. The system of C33, wherein the control valve (VI 8) is operable to block the inlet line (L2) on a first side of the control valve (VI 8) facing towards the port (P2) while opening a fluid path between a connecting line (LI 4) and the inlet line (L2) on a second side of the control valve (VI 8) facing towards the concentrate pump (FP2).

Claims

39CLAIMS1. A system for generating a treatment fluid for use in dialysis, said system comprising: a mixing arrangement (11), which is operable to mix water with one or more liquid concentrates to generate the treatment fluid, a fluid path arrangement (L) for directing the water and the one or more liquid concentrates to and through the mixing arrangement (11) and for directing the treatment fluid from the mixing arrangement (11) for use in dialysis, an input port arrangement (P2, P2') in fluid communication with the fluid path arrangement (L) and configured for releasable connection to a set of containers (7, 7') holding the one or more liquid concentrates, a heater (9), and a control arrangement (80) which is configured to: operate the system, by use of the mixing arrangement (11), to perform a sequence of time- separated sessions of generating the treatment fluid, operate the system, between the time- separated sessions and by use of the heater (9), to perform a first heat disinfection of the fluid path arrangement (L) except for a first subset (L2, AL2) of the fluid path arrangement (L) that is configured for fluid communication with the input port arrangement (P2, P2'), and operate the system to arrange at least one liquid concentrate among the one or more liquid concentrates in said first subset (L2, AL2) between the time-separated sessions.

2. The system of claim 1, wherein the control arrangement (80) is configured to arrange said at least one liquid concentrate in said first subset (L2, AL2) by operating the system to perform at least one priming operation in which said at least one liquid concentrate is supplied to said first subset (L2, AL2) via the input port arrangement (P2, P2').

3. The system of claim 1 or 2, wherein the control arrangement (80) is configured to operate the system to perform the first heat disinfection while the input port arrangement (P2, P2') is connected to at least one container in the set of containers (7, 7'), wherein said at least one container holds said at least one liquid concentrate.

4. The system of claim 2 and 3, wherein said at least one priming operation comprises a preparatory priming operation which is performed after a connection40 operation, in which said at least one container is connected to the input port arrangement (P2, P2'), and before start of said sequence of time- separated sessions of generating the treatment fluid.

5. The system of claim 3 or 4, wherein the control arrangement (80) is further configured to, while said at least one container is disconnected from the input port arrangement (P2, P2'), operate the system to perform a second heat disinfection of at least the first subset (L2, AL2) of the fluid path arrangement (L), and the input port arrangement (P2, P2').

6. The system of claim 5, wherein the second heat disinfection is performed to heat disinfect all fluid paths of the fluid path arrangement (L).

7. The system of claim 5 or 6, wherein the input port arrangement (P2, P2') comprises a port sensor arrangement (12, 12'), which is configured to provide a sensor signal indicative of disconnection of said at least one container from the input port arrangement (P2, P2') and closing of the input port arrangement (P2, P2'), and wherein the control arrangement (80) is configured to operate the system to perform the second heat disinfection when the sensor signal indicates that the input port arrangement (P2, P2') is closed and disconnected from said at least one container.

8. The system of any one of claims 3-7, wherein the control arrangement (80) is configured to cause said at least one container to be disconnected from the input port arrangement (P2, P2') after the sequence of time- separated sessions, so that the input port arrangement (P2, P2') remains connected to said at least one container throughout said sequence of time- separated sessions.

9. The system of any preceding claim, wherein said at least one liquid concentrate is bacteriostatic.

10. The system of any preceding claim, wherein the control arrangement (80) is configured to perform a dedicated action when a residence time of said at least one liquid concentrate in said first subset (L2, AL2) exceeds a predefined maximum time.

11. The system of claim 10 in combination with any one of claims 5-7, wherein said dedicated action comprises: causing said at least one container to be disconnected from the input port arrangement (P2, P2') and operating the system to perform the41 second heat disinfection; or operating the system to perform an intermittent priming operation, in which said at least one liquid concentrate is supplied to said first subset (L2, AL2) via the input port arrangement (P2, P2').

12. The system of any preceding claim, wherein the fluid path arrangement (L) consists of reusable components.

13. The system of claim 12, wherein the control arrangement (80) is configured to operate the system to perform the sequence of time-separated sessions over an extended time period, and the reusable components are configured to be maintained in the system at least throughout the extended time period.

14. The system of any preceding claim, wherein the control arrangement (80) is configured to, before the first heat disinfection, operate one or more valves (V2, V3, V5, V6, V18, V18') in the fluid path arrangement (L) to define the first subset (L2, AL2) within the fluid path arrangement (L).

15. The system of any preceding claim, wherein the fluid path arrangement (L) consists of the first subset (L2, AL2) and a second subset (LI, AL1, L3, L4, L5, AL5), wherein control arrangement (80) is configured to operate the fluid path arrangement (L) to fluidly separate the first subset (L2, AL2) from the second subset (LI, AL1, L3, L4, L5, AL5) before the first heat disinfection.

16. The system of claim 15, wherein the control arrangement (80), to perform the first heat disinfection, is configured to operate the heater (9) to heat a disinfection fluid and operate the fluid path arrangement (L) to distribute the thus-heated disinfection fluid within the second subset (LI, AL1, L3, L4, L5, AL5).

17. The system of any preceding claim, wherein the time- separated sessions are separated by a respective time interval, and wherein the control arrangement (80) is configured to operate the system to arrange said at least one liquid concentrate in the first subset (L2, AL2) throughout the respective time interval.

18. The system of any preceding claim, wherein the control arrangement (80) is configured to operate the system to perform the sequence of time-separated sessions over a time period of at least 3 days, such as 3, 4, 5, 6 or 7 days.

19. The system of any preceding claim, wherein consecutive sessions in the sequence of time-separated sessions are separated by at least 4, 6, 8, 10 or 12 hours.

20. The system of any preceding claim, wherein the control arrangement (80), to perform a respective session of generating the treatment fluid, is configured to operate the mixing arrangement (11) to mix the water with the one or more liquid concentrates.

21. The system of any preceding claim, wherein said first subset of the fluid path arrangement (L) comprises an inlet line (L2) that extends from a port (P2) in the input port arrangement (P2, P2') and is arranged for fluid communication with a concentrate pump (FP2), and an auxiliary line (L8) that extends from the port (P2) and is arranged for fluid communication with a fluid pump (FP1), wherein the control arrangement (80) is configured to, during said at least one priming operation, operate the concentrate pump (FP2) to draw a liquid concentrate via the port (P2) through the inlet line (L2); operate a valve arrangement to close the inlet line (L2); operate the valve arrangement to open fluid communication between the port (P2) and the fluid pump (FP1) via the auxiliary line (L8); operate the fluid pump (FP1) to draw the liquid concentrate via the port (P2) through the auxiliary line (L8); and operate the valve arrangement to close the auxiliary line (L8).

22. The system of claim 21, wherein the valve arrangement comprises a control valve (VI 8), which is located in the inlet line (L2) intermediate the port (P2) and the concentrate pump (FP2).

23. The system of claim 22, wherein the first heat disinfection is performed to heat disinfect the inlet line (L2) downstream of the control valve (VI 8).

24. The system of claim 22 or 23, wherein the control valve (VI 8) is operable to block the inlet line (L2) on a first side of the control valve (VI 8) facing towards the port (P2) while opening a fluid path between a connecting line (LI 4) and the inlet line (L2) on a second side of the control valve (VI 8) facing towards the concentrate pump (FP2).

25. The system of any one of claims 21-24, wherein the input port arrangement (P2, P2') is configured to define an internal chamber (73, 74) in fluid communication with the fluid path arrangement (L) when said at least one container is disconnected from the input port arrangement (P2, P2') , and wherein the second heat disinfection isperformed to heat disinfect the inlet line (L2), the internal chamber (73, 74), and the auxiliary line (L8).

26. The system of any preceding claim, wherein the control arrangement (80) is configured to operate the system, by use of the mixing arrangement (11), to perform each of the time-separated sessions to generate treatment fluid for use in peritoneal dialysis.

27. The system of claim 26, wherein said each of the time- separated sessions corresponds to a respective treatment session of said peritoneal dialysis, wherein the treatment fluid generated in said each of the time- separated sessions is consumed during the respective treatment session.

28. The system of claim 27, wherein the respective treatment session comprises a plurality of fluid exchange cycles, each comprising a fill phase, a dwell phase and a drain phase.

29. The system of any preceding claim, wherein the control arrangement (80) is configured to operate the system, by use of the mixing arrangement (11), to perform each of the time-separated sessions to generate treatment fluid for use in extracorporeal blood dialysis.

30. A computer-implemented method of operating a system for generating a treatment fluid for use in dialysis, said method comprising: operating a mixing arrangement (11) in the system to perform time- separated sessions of generating the treatment fluid by mixing water with one or more liquid concentrates, wherein a fluid path arrangement (L) directs the water and the one or more liquid concentrates to and through the mixing arrangement (11), and directs the treatment fluid from the mixing arrangement (11) for use in dialysis, and wherein the one or more liquid concentrates are supplied via an input port arrangement (P2, P2') which is releasably connected to a set of containers (7, 7') that hold the one or more liquid concentrates, operating the system to, between the time-separated sessions and by use of a heater (9), perform a first heat disinfection of the fluid path arrangement (L) except for a first subset (L2, AL2) of the fluid path arrangement (L) that is in fluid communication with the input port arrangement (P2, P2'), and44 operating the system to arrange at least one liquid concentrate among the one or more liquid concentrates in said first subset (L2, AL2) between the time-separated sessions.

31. A computer-readable medium comprising program instructions, which when executed by processor circuitry (81), causes the processor circuitry (81) to perform the method of claim 30.

32. A system for generating a treatment fluid for use in dialysis, said system comprising: a mixing arrangement (11), which is operable to mix water with one or more liquid concentrates to generate the treatment fluid, a fluid path arrangement (L) for directing the water and the one or more liquid concentrates to and through the mixing arrangement (11) and for directing the treatment fluid from the mixing arrangement (11) for use in dialysis, an input port arrangement (P2, P2') in fluid communication with the fluid path arrangement (L) and configured for releasable connection to a set of containers (7, 7') holding the one or more liquid concentrates, wherein the fluid path arrangement comprises an inlet line (L2) that extends from a port (P2) in the input port arrangement (P2, P2') and is arranged for fluid communication with a concentrate pump (FP2), and an auxiliary line (L8) that extends from the port (P2) and is arranged for fluid communication with a fluid pump (FP1), wherein the fluid path arrangement further comprises a valve arrangement which is operable to selectively open and close the inlet line (L2) and selectively open and close fluid communication between the port (P2) and the fluid pump (FP1) via the auxiliary line (L8).

33. The system of claim 32, wherein the valve arrangement comprises a control valve (VI 8), which is located in the inlet line (L2) intermediate the port (P2) and the concentrate pump (FP2).

34. The system of claim 33, wherein the control valve (VI 8) is operable to block the inlet line (L2) on a first side of the control valve (VI 8) facing towards the port (P2) while opening a fluid path between a connecting line (LI 4) and the inlet line (L2) on a second side of the control valve (VI 8) facing towards the concentrate pump (FP2).

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